Stimulation of phosphoinositide hydrolysis via class I antigen‐specific recognition in murine cardiac tissue

Abstract

Induction of polyphosphoinositide hydrolysis in cardiac tissue by specific recognition of class I histocompatibility antigens was assayed. C3H (H-2 k) mice auricles were labelled with myo-pH]inositol precursor and inositol phosphate production in the presence or absence of anti-class I k products was measured. Anti-class I, but not anti-class II products specifically increased phosphoinositide turnover. This increment was partially blocked by muscarinic cholinergic and ct-adrenergic blockers and even more so by the phospholipase C inhibitor NCDC. Alloantibodies specifically directed against class I antigens could then exert stimulation of phospholipase C-mediated phosphoinositide hydrolysis through the interaction with muscarinic cholinergic and/or ~-adrenergic receptors. The induction of intraceUular second messengers by class I antigens and hormone-receptor interactions is discussed.

Calcium oscillations in interstitial cells of the rabbit urethra

“…Another approach to assessing the role of IP 3 in the genesis and modulation of Ca 2+ oscillations in the intersitial cells was to inhibit the enzyme necessary for its production. We used two different compounds for this purpose, NCDC (Cremaschi & Sterin‐Borda, 1989; Gotoh et al 1993) and U73122 (Smith et al 1990). Figure 4 shows the effect of 100 μ m NCDC on frequency and amplitude of Ca 2+ oscillations.…”

Circulating antibodies against rat parotid gland M3 muscarinic receptors in primary Sjögren’s syndrome

“…Fractions of 1 ml were recovered and radioactivity determined by scintillation counting. Results were expressed as the absolute values of the area under the curve following the criteria of Simpson's equation, and in order to determine the absence of 3 H-MI in the IPs eluted phase, chromatography on silica gel 60 F 254 sheets (Merck) was performed as described before [7,[24][25][26].…”